Psychology Author:John Dewey Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: PART I.—KNOWLEDGE. CHAPTER III. ELEMENTS OP KNOWLEDGE. § 1. /Sensation in General. Definition.—The elements of intelligence which, through their combin... more »ations, constitute knowledge are termed sensations. Sentience is the term, used to express the capability of the mind for sensations, while the specific organs which realize this capacity are called sensory, or simply the senses. A sensation may be geoerically defined as any consciousness arising in the self through some bodily occasion. More specifically, it is the elementary consciousness which arises from the reaction of the soul upon a nervous impulse conducted to the brain from the affection of some sensory nerve-ending by a physical stimulus. Treatment of Subject.—A sensation is thus seen to involve two elements—a physical and a psychical. It is concerned, on the one hand, with the body; on the other with the soul. The physical factor may be considered with reference either to the stimulus which affects the nerve organ, or with relation to the nerve activity itself. We shall consider, accordingly, the following topics under the head of sensation : I. The physical stimulus in its broad sense, including subdivisions into the extra-organic stimulus and the physiological.II. The psychical element, or sensation proper. III. The relation between the physical and the psychical factors. IV. The function of sensation in intellectual life. I. The Physical Stimulus. 1. Extra-organic Stimulus.—While a few of our sensations arise from operations going on within our own body, the larger number, and those most important in their cognitive aspect, originate in affections of the organism by something external to it. Things just about us affect the organs of touch; bodies still more remote impinge upon us through the sense of...« less